- Reversibility of Disease: Demonstrated a ≥ 12% and ≥200mL reversibility of FEV1 within approximately 30-minutes following 4 inhalations of albuterol/salbutamol inhalation aerosol (if required, spacers are permitted for reversibility testing only) or one nebulized albuterol/salbutamol solution at the Screening Visit. If a subject fails to demonstrate an increase in FEV1 ≥12% and ≥200mL, then the subject is not eligible for the study and will not be allowed to re-screen.